i18n_variable: backdrop_multilingual() does not exist

[herbdool]

I get a fatal error on updating from d7 where it gets an undefined function backdrop_multilingual() which gets called in hook_init so pretty much all the time. When starting the upgrade i18n_variable is still enabled so we need to ensure this doesn't break things.

[indigoxela]

It seems that the hidden i18n_variable module causes several problems when upgrading.

The function should be: language_multilingual() (was drupal_multilingual() before).

Fix is (hopefully) on the way. See c466383

[indigoxela]

Fixed. In the meantime all code from deprecated modules got removed.